GZA is managing the investigation and/or remediation of four former manufactured gas plant (MGP) sites in the Mid-Atlantic region.


The hydrogeologic conditions are complex and vary dramatically at each site. Active use of several sites and third-party ownership requires additional planning and collaboration. The on-site presence of NAPL, potentially impacting an adjacent water body, adds complexity to the investigation and potential remediation of one of the sites.


GZA reviewed historical site data, developed Conceptual Site Models (CSMs) and designed targeted remedial investigations and remedial actions for these sites. Access agreements were successfully negotiated for sites owned by third parties. Investigation techniques included geophysical surveys and test pits to evaluate presence/absence of MGP historical structures; vibracores and soil borings to evaluate sediments in adjacent water bodies and soil impacts; and overburden and bedrock wells to evaluate presence/absence of NAPL and groundwater quality


GZA’s MGP expertise and understanding of compliance demands unique to this industry have allowed us to assist the client with regulatory negotiations and budget forecasting. To date, two of these legacy sites have received regulatory closure.